I'm trying to create a simple slide in animation for an existing recycler view.
Lets say the recycler holds 50 items, at some point the dataset has change and now contains only 40 items, the items have been replaced, all the previous 50 items are not relevant anymore.
So, notifyDatasetChanged() is being called after the data structure has been modified and the new items are animated in.
The problem is you can still see the previous 40 items below the new items, on the same space of each cell, you see both the previous data and the new data.
the code for ItemAnimator subclass is below, if I add a remove animation that changes the opacity of the remove cell it will be invisible but the item decoration (list lines) are not removed, I would prefer to remove the items entirely and not make it invisible.
public class RVSlideAnimation extends RecyclerView.ItemAnimator {
List<RecyclerView.ViewHolder> mViewHolders = new ArrayList<RecyclerView.ViewHolder>();
#Override
public void runPendingAnimations() {
if (!mViewHolders.isEmpty()) {
int animationDuration = 250;
AnimatorSet animator;
View target;
for (final RecyclerView.ViewHolder viewHolder : mViewHolders) {
target = viewHolder.itemView;
target.setPivotX(target.getMeasuredWidth() / 2);
target.setPivotY(target.getMeasuredHeight() / 2);
animator = new AnimatorSet();
animator.playTogether(
ObjectAnimator.ofFloat(target, "translationX", target.getMeasuredWidth(), 0.0f),
ObjectAnimator.ofFloat(target, "alpha", target.getAlpha(), 1.0f)
);
animator.setTarget(target);
animator.setDuration(animationDuration);
animator.setInterpolator(new AccelerateDecelerateInterpolator());
animator.setStartDelay((animationDuration * viewHolder.getAdapterPosition()) / 10);
animator.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animation) {
}
#Override
public void onAnimationEnd(Animator animation) {
mViewHolders.remove(viewHolder);
}
#Override
public void onAnimationCancel(Animator animation) {
}
#Override
public void onAnimationRepeat(Animator animation) {
}
});
animator.start();
}
}
}
#Override
public boolean animateRemove(RecyclerView.ViewHolder viewHolder) {
//viewHolder.itemView.animate().alpha(0).setDuration(100);
return false;
}
#Override
public boolean animateAdd(RecyclerView.ViewHolder viewHolder) {
viewHolder.itemView.setAlpha(0.0f);
return mViewHolders.add(viewHolder);
}
#Override
public boolean animateMove(RecyclerView.ViewHolder viewHolder, int i, int i2, int i3, int i4) {
return false;
}
#Override
public boolean animateChange(RecyclerView.ViewHolder oldHolder, RecyclerView.ViewHolder newHolder, int fromLeft, int fromTop, int toLeft, int toTop) {
return false;
}
#Override
public void endAnimation(RecyclerView.ViewHolder viewHolder) {
}
#Override
public void endAnimations() {
}
#Override
public boolean isRunning() {
return !mViewHolders.isEmpty();
}
}
recyclerView.destroyDrawingCache(); before notifyDatasetChaged() solved the issue for me.
Related
I'm creating a Q&A where each question is a card. The answer starts showing the first line, but when its clicked it should expanded to show the full answer.
When an answer is expanded/collapsed the rest of the RecyclerView should animate to make room for the expansion or collapse to avoid showing a blank space.
I watched the talk on RecyclerView animations, and believe I want a custom ItemAnimator, where I override animateChange. At that point I should create an ObjectAnimator to animate the height of the View's LayoutParams. Unfortunately I'm having a hard time tying it all together. I also return true when overriding canReuseUpdatedViewHolder, so we reuse the same viewholder.
#Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
return true;
}
#Override
public boolean animateChange(#NonNull RecyclerView.ViewHolder oldHolder,
#NonNull final RecyclerView.ViewHolder newHolder,
#NonNull ItemHolderInfo preInfo,
#NonNull ItemHolderInfo postInfo) {
Log.d("test", "Run custom animation.");
final ColorsAdapter.ColorViewHolder holder = (ColorsAdapter.ColorViewHolder) newHolder;
FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) holder.tvColor.getLayoutParams();
ObjectAnimator halfSize = ObjectAnimator.ofInt(holder.tvColor.getLayoutParams(), "height", params.height, 0);
halfSize.start();
return super.animateChange(oldHolder, newHolder, preInfo, postInfo);
}
Right now I'm just trying to get something to animate, but nothing happens... Any ideas?
I think your animation was not working because you cannot animate LayoutParams that way although it would be neat if you could. I tried the code you had and all it did was make my view jump to the new height. Only way I found to get this to work was to use a ValueAnimator as you can see in the example below.
I noticed some shortcomings when using the DefaultItemAnimator to show/hide a view by updating its visibility. Although it did make room for the new view and animated the rest of the items up and down based on the visibility of the expandable view, I noticed it did not animate the height of the expandable view. It simply faded into place and out of place using alpha value only.
Below is a custom ItemAnimator that has size and alpha animations based on hiding/showing a LinearLayout in the ViewHolder layout. It also allows the reuse of the same ViewHolder and attempts handling partial animations correctly if the user taps the header quickly:
public static class MyAnimator extends DefaultItemAnimator {
#Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
return true;
}
private HashMap<RecyclerView.ViewHolder, AnimatorState> animatorMap = new HashMap<>();
#Override
public boolean animateChange(#NonNull RecyclerView.ViewHolder oldHolder, #NonNull final RecyclerView.ViewHolder newHolder, #NonNull ItemHolderInfo preInfo, #NonNull ItemHolderInfo postInfo) {
final ValueAnimator heightAnim;
final ObjectAnimator alphaAnim;
final CustomAdapter.ViewHolder vh = (CustomAdapter.ViewHolder) newHolder;
final View expandableView = vh.getExpandableView();
final int toHeight; // save height for later in case reversing animation
if(vh.isExpanded()) {
expandableView.setVisibility(View.VISIBLE);
// measure expandable view to get correct height
expandableView.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
toHeight = expandableView.getMeasuredHeight();
alphaAnim = ObjectAnimator.ofFloat(expandableView, "alpha", 1f);
} else {
toHeight = 0;
alphaAnim = ObjectAnimator.ofFloat(expandableView, "alpha", 0f);
}
heightAnim = ValueAnimator.ofInt(expandableView.getHeight(), toHeight);
heightAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
expandableView.getLayoutParams().height = (Integer) heightAnim.getAnimatedValue();
expandableView.requestLayout();
}
});
AnimatorSet animSet = new AnimatorSet()
.setDuration(getChangeDuration());
animSet.playTogether(heightAnim, alphaAnim);
animSet.addListener(new Animator.AnimatorListener() {
private boolean isCanceled;
#Override
public void onAnimationStart(Animator animation) { }
#Override
public void onAnimationEnd(Animator animation) {
if(!vh.isExpanded() && !isCanceled) {
expandableView.setVisibility(View.GONE);
}
dispatchChangeFinished(vh, false);
animatorMap.remove(newHolder);
}
#Override
public void onAnimationCancel(Animator animation) {
isCanceled = true;
}
#Override
public void onAnimationRepeat(Animator animation) { }
});
AnimatorState animatorState = animatorMap.get(newHolder);
if(animatorState != null) {
animatorState.animSet.cancel();
// animation already running. Set start current play time of
// new animations to keep them smooth for reverse animation
alphaAnim.setCurrentPlayTime(animatorState.alphaAnim.getCurrentPlayTime());
heightAnim.setCurrentPlayTime(animatorState.heightAnim.getCurrentPlayTime());
animatorMap.remove(newHolder);
}
animatorMap.put(newHolder, new AnimatorState(alphaAnim, heightAnim, animSet));
dispatchChangeStarting(newHolder, false);
animSet.start();
return false;
}
public static class AnimatorState {
final ValueAnimator alphaAnim, heightAnim;
final AnimatorSet animSet;
public AnimatorState(ValueAnimator alphaAnim, ValueAnimator heightAnim, AnimatorSet animSet) {
this.alphaAnim = alphaAnim;
this.heightAnim = heightAnim;
this.animSet = animSet;
}
}
}
This is the result using a slightly modified RecyclerView demo.
Update:
Just noticed your use case is actually a bit different after rereading the question. You have a text view and only want to show a single line of it and then later expand it to show all lines. Fortunately that simplifies the custom animator:
public static class MyAnimator extends DefaultItemAnimator {
#Override
public boolean canReuseUpdatedViewHolder(RecyclerView.ViewHolder viewHolder) {
return true;
}
private HashMap<RecyclerView.ViewHolder, ValueAnimator> animatorMap = new HashMap<>();
#Override
public boolean animateChange(#NonNull RecyclerView.ViewHolder oldHolder, #NonNull final RecyclerView.ViewHolder newHolder, #NonNull ItemHolderInfo preInfo, #NonNull ItemHolderInfo postInfo) {
ValueAnimator prevAnim = animatorMap.get(newHolder);
if(prevAnim != null) {
prevAnim.reverse();
return false;
}
final ValueAnimator heightAnim;
final CustomAdapter.ViewHolder vh = (CustomAdapter.ViewHolder) newHolder;
final TextView tv = vh.getExpandableTextView();
if(vh.isExpanded()) {
tv.measure(View.MeasureSpec.makeMeasureSpec(((View) tv.getParent()).getWidth(), View.MeasureSpec.AT_MOST), View.MeasureSpec.UNSPECIFIED);
heightAnim = ValueAnimator.ofInt(tv.getHeight(), tv.getMeasuredHeight());
} else {
Paint.FontMetrics fm = tv.getPaint().getFontMetrics();
heightAnim = ValueAnimator.ofInt(tv.getHeight(), (int)(Math.abs(fm.top) + Math.abs(fm.bottom)));
}
heightAnim.setDuration(getChangeDuration());
heightAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
tv.getLayoutParams().height = (Integer) heightAnim.getAnimatedValue();
tv.requestLayout();
}
});
heightAnim.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationEnd(Animator animation) {
dispatchChangeFinished(vh, false);
animatorMap.remove(newHolder);
}
#Override
public void onAnimationCancel(Animator animation) { }
#Override
public void onAnimationStart(Animator animation) { }
#Override
public void onAnimationRepeat(Animator animation) { }
});
animatorMap.put(newHolder, heightAnim);
dispatchChangeStarting(newHolder, false);
heightAnim.start();
return false;
}
}
And the new demo:
You don't have to implement a custom ItemAnimator the default DefaultItemAnimator already supports what you need. However you need to tell this Animator which views changed. I guess you are calling notifyDataSetChanged() in your adapter. This prevents the animation for a single changed item in the RecyclerView (in your case the expand/collapse of the item).
You should use notifyItemChanged(int position) for the items that were changed. Here is a short itemClicked(int position) method that expands/collapses views in the RecyclerView. The field expandedPosition keeps track of the currently expanded item:
private void itemClicked(int position) {
if (expandedPosition == -1) {
// selected first item
expandedPosition = position;
notifyItemChanged(position);
} else if (expandedPosition == position) {
// collapse currently expanded item
expandedPosition = -1;
notifyItemChanged(position);
} else {
// collapse previously expanded item and expand new item
int oldExpanded = expandedPosition;
expandedPosition = position;
notifyItemChanged(oldExpanded);
notifyItemChanged(position);
}
}
This is the result:
According the documentation, you need to return false in animateChange or call runPendingAnimations later. Try returning false.
http://developer.android.com/reference/android/support/v7/widget/RecyclerView.ItemAnimator.html
Try this class:
import android.animation.Animator;
import android.animation.ValueAnimator;
import android.graphics.Paint;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.widget.TextView;
/**
* Created by ankitagrawal on 2/14/16.
*/
public class AnimatedViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener {
private int originalHeight = 0;
private boolean mIsViewExpanded = false;
private TextView textView;
// ..... CODE ..... //
public AnimatedViewHolder(View v) {
super(v);
v.setOnClickListener(this);
// Initialize other views, like TextView, ImageView, etc. here
// If isViewExpanded == false then set the visibility
// of whatever will be in the expanded to GONE
if (!mIsViewExpanded) {
// Set Views to View.GONE and .setEnabled(false)
textView.setLines(1);
}
}
#Override
public void onClick(final View view) {
// Declare a ValueAnimator object
ValueAnimator valueAnimator;
if(mIsViewExpanded) {
view.measure(View.MeasureSpec.makeMeasureSpec(((View) view.getParent()).getWidth(), View.MeasureSpec.AT_MOST), View.MeasureSpec.UNSPECIFIED);
mIsViewExpanded = false;
valueAnimator = ValueAnimator.ofInt(view.getHeight(), view.getMeasuredHeight());
} else {
Paint.FontMetrics fm = ((TextView)view).getPaint().getFontMetrics();
valueAnimator = ValueAnimator.ofInt(view.getHeight(), (int) (Math.abs(fm.top) + Math.abs(fm.bottom)));
mIsViewExpanded = true;
}
valueAnimator.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationEnd(Animator animation) {
}
#Override
public void onAnimationCancel(Animator animation) { }
#Override
public void onAnimationStart(Animator animation) { }
#Override
public void onAnimationRepeat(Animator animation) { }
});
valueAnimator.setDuration(200);
valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
view.getLayoutParams().height = (Integer) animation.getAnimatedValue();
view.requestLayout();
}
});
valueAnimator.start();
}
}
The Advantage of this approach is it only add animation to onClick event and that best suits your requirement.
adding animation to viewholder will be too burdensome to your requirement.
and itemAnimator as per doc are animation for layout out items so also not best suits your requirement.
For expand & collapse animation android there is github library for it.
ExpandableRecyclerView
1).Add dependencies in the build.gradle file
dependencies {
compile 'com.android.support:recyclerview-v7:22.2.0'
compile 'com.bignerdranch.android:expandablerecyclerview:1.0.3'
}
Image of Expand & Collapse Animation
2) Expand & Collapse animation for RecyclerView animation
public static class ExampleViewHolder extends RecyclerView.ViewHolder
implements View.OnClickListener {
private int originalHeight = 0;
private boolean isViewExpanded = false;
private YourCustomView yourCustomView
public ExampleViewHolder(View v) {
super(v);
v.setOnClickListener(this);
// Initialize other views, like TextView, ImageView, etc. here
// If isViewExpanded == false then set the visibility
// of whatever will be in the expanded to GONE
if (isViewExpanded == false) {
// Set Views to View.GONE and .setEnabled(false)
yourCustomView.setVisibility(View.GONE);
yourCustomView.setEnabled(false);
}
}
#Override
public void onClick(final View view) {
// If the originalHeight is 0 then find the height of the View being used
// This would be the height of the cardview
if (originalHeight == 0) {
originalHeight = view.getHeight();
}
// Declare a ValueAnimator object
ValueAnimator valueAnimator;
if (!mIsViewExpanded) {
yourCustomView.setVisibility(View.VISIBLE);
yourCustomView.setEnabled(true);
mIsViewExpanded = true;
valueAnimator = ValueAnimator.ofInt(originalHeight, originalHeight + (int) (originalHeight * 2.0)); // These values in this method can be changed to expand however much you like
} else {
mIsViewExpanded = false;
valueAnimator = ValueAnimator.ofInt(originalHeight + (int) (originalHeight * 2.0), originalHeight);
Animation a = new AlphaAnimation(1.00f, 0.00f); // Fade out
a.setDuration(200);
// Set a listener to the animation and configure onAnimationEnd
a.setAnimationListener(new Animation.AnimationListener() {
#Override
public void onAnimationStart(Animation animation) {
}
#Override
public void onAnimationEnd(Animation animation) {
yourCustomView.setVisibility(View.INVISIBLE);
yourCustomView.setEnabled(false);
}
#Override
public void onAnimationRepeat(Animation animation) {
}
});
// Set the animation on the custom view
yourCustomView.startAnimation(a);
}
valueAnimator.setDuration(200);
valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
Integer value = (Integer) animation.getAnimatedValue();
view.getLayoutParams().height = value.intValue();
view.requestLayout();
}
});
valueAnimator.start();
}
}
Hope this will help you.
I have a custom view kind of like a progress bar. inside this view i have an ObjectAnimator.AnimatorUpdateListener which i'm trying to use to call invalidate on the view. However, my view is not updating! I tried to add a button which simply changed the value to something else and called invalidate once and it worked, my view updated to reflect the value change.
Am I missing something here? Am I calling invalidate too many times or something?
My "progressbar" starts with a float at 0, and the animation is supposed to animate it to 100. Calling a method to update it to 50 and call invalidate works, but the ObjectAnimator doesnt seem to be calling invalidate.
Everything is being called on the UI Thread
ObjectAnimator does not call invalidate() - your method should do it when needed
ObjectAnimator oAnimator = ObjectAnimator.ofInt(view,"someproperty",0,100)
void setSomeProperty(value) {
mValue = value
invalidate()
}
I have used this and it worked.
public interface ProgressAnimationListener {
public void onAnimationStart();
public void onAnimationFinish();
public void onAnimationProgress(int progress);
}
private ObjectAnimator progressBarAnimator;
public synchronized void animateProgressTo(final int start, final int end, final int duration, final ProgressAnimationListener listener) {
stopAnimation();
setProgress(start);
progressBarAnimator = ObjectAnimator.ofFloat(this, "animateProgress", start, end);
progressBarAnimator.setDuration(duration);
progressBarAnimator.setInterpolator(new LinearInterpolator());
progressBarAnimator.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationCancel(final Animator animation) {
}
#Override
public void onAnimationEnd(final Animator animation) {
setProgress(end);
if (listener != null) {
listener.onAnimationFinish();
}
}
#Override
public void onAnimationRepeat(final Animator animation) {
}
#Override
public void onAnimationStart(final Animator animation) {
if (listener != null) {
listener.onAnimationStart();
}
}
});
progressBarAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(final ValueAnimator animation) {
int progress = ((Float) animation.getAnimatedValue()).intValue();
if (progress != getProgress()) {
//Log.d(TAG, progress + "");
setProgress(progress);
if (listener != null) {
listener.onAnimationProgress(progress);
}
}
}
});
progressBarAnimator.start();
}
public synchronized boolean isAnimationRunning() {
return progressBarAnimator != null && progressBarAnimator.isRunning();
}
public synchronized void stopAnimation() {
if (isAnimationRunning()) {
progressBarAnimator.cancel();
progressBarAnimator = null;
}
}
I can't get the circular reveal animation to work.
I think I checked the most obvious things:
It starts, width and height are > 0 and it is visible, no Exception..
I load some data from the internet and display it in the view(fab)
The animation should only play after the download finishes.
TmdbHelper helper = new TmdbHelper();
helper.getMovieById(id, "en", new TmdbHelper.ResultListener() {
#Override
public void onResultReceived(JSONObject result) {
// called when finished downloading
try {
String rating = result.getString("vote_average");
AnimationHelper.circularReveal(fab, 500, 0);
fab.setText(rating);
} catch (JSONException e) {
e.printStackTrace();
}
}
});
AnimationHelper:
public static void circularReveal(final View view, final long duration, long startDelay) {
// get the center for the clipping circle
int cx = (view.getLeft() + view.getRight()) / 2;
int cy = (view.getTop() + view.getBottom()) / 2;
// get the final radius for the clipping circle
int finalRadius = Math.max(view.getWidth(), view.getHeight());
// create the animator for this view (the start radius is zero)
Animator anim =
ViewAnimationUtils.createCircularReveal(view, cx, cy, 0, finalRadius);
anim.setDuration(duration);
anim.setStartDelay(startDelay);
anim.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animation) {
view.setVisibility(View.VISIBLE);
}
#Override
public void onAnimationEnd(Animator animation) {
}
#Override
public void onAnimationCancel(Animator animation) {
}
#Override
public void onAnimationRepeat(Animator animation) {}
});
// make the view visible and start the animation
anim.start();
}
I use the circular reveal animation in other parts like this to make sure the view is attached, and it works:
headerContainer.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
headerContainer.getViewTreeObserver().removeOnGlobalLayoutListener(this);
AnimationHelper.circularReveal(headerContainer, 500, 200);
}
});
Perhaps you should erase this line inside your onResultRecieved():
fab.setVisibility(View.VISIBLE);
My assumption is that your circular reveal method is working just fine. It is because of you have made the FAB visible before the animation even begin, you can't see it in action.
As an addition, those lines you've shown which is working doesn't have fab.setVisibility(View.VISIBLE) called anywhere in it.
1st Approach:
Try Transition Listener.
getWindow().getSharedElementExitTransition().addListener(new Transition.TransitionListener() {
#Override
public void onTransitionStart(Transition transition) {
}
#Override
public void onTransitionEnd(Transition transition) {
}
#Override
public void onTransitionCancel(Transition transition) {
}
#Override
public void onTransitionPause(Transition transition) {
}
#Override
public void onTransitionResume(Transition transition) {
}
});
2nd Approach: Try setting start delay and listener to the reveal animation and when animation starts then set the view visible
if (Build.VERSION.SDK_INT >= 21) {
Animator anim = ViewAnimationUtils.createCircularReveal(viewRoot, cx, cy, 0, finalRadius);
anim.setStartDelay(300);
anim.setDuration(1000);
anim.setInterpolator(new DecelerateInterpolator());
anim.addListener(new Animator.AnimatorListener() {
#Override
public void onAnimationStart(Animator animation) {
viewRoot.setVisibility(View.VISIBLE);
}
#Override
public void onAnimationEnd(Animator animation) {
}
#Override
public void onAnimationCancel(Animator animation) {
}
#Override
public void onAnimationRepeat(Animator animation) {
}
});
anim.start();
}
}
#Override
public void onAnimationCancel(Animator animation) {
}
#Override
public void onAnimationRepeat(Animator animation) {
}
});
anim.start();
I have a button in my layout. And I am animating the position of that button using ObjectAnimator with translationX animation.
ObjectAnimator btnAnimator = ObjectAnimator.ofFloat(myBtn, "translationX",
ViewHelper.getTranslationX(myBtn), 0);
btnAnimator.addListener(new AnimatorListener() {
#Override
public void onAnimationCancel(Animator arg0) {}
#Override
public void onAnimationEnd(Animator arg0) {
Log.i("TAG","Animation Finished");
}
#Override
public void onAnimationRepeat(Animator arg0) {}
#Override
public void onAnimationStart(Animator arg0) {}
});
btnAnimator.setDuration(animationSpeed).start();
Now I would like to have a listener for the TranslationX of that button to notify whenever the TranslationX position of the button changes.
Here's an easy way I found to do what you're after:
btnAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(ValueAnimator animation) {
Log.e("TAG", "translateX: "+animation.getAnimatedValue("translationX"));
}
});
btnAnimator.setDuration(animationSpeed).start();
Two possible approaches:
1) Override onLayout() in your view to manually compare and detect position changes.
2) Use onLayoutChangeListener on your View:
button.addOnLayoutChangeListener(new OnLayoutChangeListener() {
#Override
public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft,
int oldTop, int oldRight, int oldBottom) {
// Check your new position vs the old one
}
});
I used this and it worked as a decent way of listening for changes of the view translation.
var previousTranslationX = view.translationX
var previousTranslationY = view.translationY
view.viewTreeObserver.addOnDrawListener {
if (previousTranslationX != view.translationX ||
previousTranslationY != view.translationY) {
previousTranslationX = view.translationX
previousTranslationY = view.translationY
dispatchViewTranslationUpdated(view)
}
}
Simply register a callback to be invoked when the view tree is about to be drawn.
Note: This listener almost called every time the view is drawn!
public class MyView extends View {
private float oldScaleX;
public MyView(Context context) {
super(context);
getViewTreeObserver().addOnDrawListener(new ViewTreeObserver.OnDrawListener() {
#Override
public void onDraw() {
// Many things can invoke this method! We don't know why view going
// to be redrawn, So we must determine the cause ourselves.
float newScaleX=getScaleX();
if (oldScaleX!=newScaleX) {
scaleXUpdated();
oldScaleX=newScaleX;
}
}
});
}
private void scaleXUpdated() {
Log.e(TAG,"scaleX updated "+getScaleX);
}
}
I want to play one animation with multiple views in android.
This is the simplified example of code.
This code works incorrectly.
Every startAnimation() call, affects all previously animated views
Please tell me, why it doesn't works and how to make it properly.
public SomeClass() {
private int currentViewID = 0;
private View[] views = { view1, view2, view3, view4, view5 }
private Animation anim = AnimationUtils.loadAnimation(this.getContext(), android.R.anim.fade_out);
public SomeClass() {
this.anim.setAnimationListener(new Animation.AnimationListener() {
#Override
public void onAnimationEnd(Animation animation) {
if (SomeClass.this.currentViewID != SomeClass.this.views.length) SomeClass.this.hideNextView();
}
#Override
public void onAnimationRepeat(Animation animation) {
}
#Override
public void onAnimationStart(Animation animation) {
}
});
this.hideNextView();
}
private void hideNextView() {
this.views[this.currentViewID++].startAnimation(this.anim);
}
}
If you don't want to deal with many Animations in your class (one for each View) you could do things locally:
private int currentViewID = 0;
private View[] views = { view1, view2, view3, view4, view5 }
public SomeClass() {
this.hideNextView();
}
private void hideNextView() {
final Animation anim = AnimationUtils.loadAnimation(this.getContext(), android.R.anim.fade_out);
anim.setAnimationListener(new Animation.AnimationListener() {
#Override
public void onAnimationEnd(Animation animation) {
if (SomeClass.this.currentViewID != SomeClass.this.views.length) SomeClass.this.hideNextView();
}
#Override
public void onAnimationRepeat(Animation animation) {}
#Override
public void onAnimationStart(Animation animation) {}
});
this.views[this.currentViewID++].startAnimation(anim);
}